L-Glutamine
Performance
Also known as: L-Glutamine, Glutamine peptides
B
Grade B💊 5-10g daily🎯 3 primary uses🔗 2 synergies⚠️ Review warnings
Levels upFitness+50 pts
Overview
Conditionally essential amino acid. Supports gut health and immune function, less for muscle.
Primary Uses
Gut healthImmune supportRecovery
Frequently Asked About L-Glutamine
How much L-Glutamine should I take?
The typical effective range is 5-10g daily. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.
When is the best time to take L-Glutamine?
Post-workout or before bed. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.
Should I take L-Glutamine with food?
Either.
Does L-Glutamine interact with medications?
Yes — known interactions include Lactulose and Chemotherapy drugs. If you take any prescription medication, talk to your doctor or pharmacist before starting L-Glutamine.
What does L-Glutamine pair well with?
L-Glutamine stacks well with Probiotics and Zinc — these combinations either improve absorption or work synergistically toward common goals.
Who should not take L-Glutamine?
L-Glutamine should be avoided or used with caution by people with Liver disease (caution) and Kidney disease (caution). Pregnant or breastfeeding women should consult a healthcare provider before use.
What are the side effects of L-Glutamine?
Most people tolerate L-Glutamine well. The most commonly reported side effects are Generally well tolerated. Side effects are usually dose-dependent — lowering the dose often resolves them.
Dosage
Typical range
5-10g daily
Timing
Post-workout or before bed
With food
Either
Duration
During heavy training or gut issues
Special Populations
Gut issues, heavy training, immune stress
Research & Studies
Search the literature now
We haven’t curated landmark studies for L-Glutamineyet — one-click into the primary literature here. PubMed (RCTs) is usually the highest-signal starting point.
Mechanism of Action
- • Most abundant amino acid
- • Fuel for gut cells and immune cells
- • Depleted by stress and exercise
Evidence Quality
Evidence Grade B
Good for gut/immune, less for muscle (unless deficient)
Safety & Contraindications
Serious Warnings
- • None at normal doses
Contraindications
- • Liver disease (caution)
- • Kidney disease (caution)
Common Side Effects
- • Generally well tolerated
Pregnancy & Breastfeeding
Consult healthcare provider
Liver & Kidney Notes
Caution with liver/kidney disease
Interactions
💊 Medications
- • Lactulose
- • Chemotherapy drugs
🧪 Supplements
- • Most supplements
🍽️ Food & Alcohol
- • No interactions
Stacking & Synergies
Pairs Well With
Avoid Combining With
Nothing
Best Goal Synergies
Gut healthImmune support
Buying Guide
What to Look For
- • Pure L-Glutamine
Standardization Markers
L-Glutamine form
Adulteration risk
Low
Practical Notes
- • Better for gut/immune than muscle
- • Depleted by stress
Tags
amino acidgutimmunerecovery
Top Products with L-Glutamine
Highest-scored catalog products containing L-Glutamine, ranked by our scoring engine.
EnteroMend®Thorne93
Creatine + BCAAsThorne92
L-Glutamine PowderThorne92
Post Workout SupplementTransparent Labs90
More in Performance
Other ingredients in the Performance category.
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Arginine metabolite with nitric oxide and pain-modulating effects. Enhances pumps.
Arachidonic Acid (ARA)
Omega-6 fatty acid that amplifies exercise-induced muscle signaling. Increases training response but also inflammation.
BCAAs
A branched-chain amino acid blend in a 2:1:1 leucine-to-isoleucine-to-valine ratio, formulated in instantized (micronized) form for improved solubility. BCAAs support muscle protein synthesis and may reduce exercise-induced fatigue, though whole protein sources provide comparable benefits at lower cost.
Beetroot / Nitrates
Dietary nitrates converted to nitric oxide for improved endurance and blood flow. Can enhance exercise efficiency.
Beta-Alanine
Increases muscle carnosine for buffering acid during high-intensity exercise. Delays fatigue in 1-4 minute efforts.
Beta-Hydroxybutyrate (BHB)
Exogenous ketone body that can elevate blood ketone levels. Used for energy, cognitive function, and supporting ketogenic diets.
Last reviewed: September 2026 by the Formulate Research Team. Sources cited above; methodology and scoring criteria published here.
Cite this page
Formulate Research Team. (2026, September). L-Glutamine — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/glutamine
Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.